The development of new materials for Additive Manufacturing (AM), especially for Laser Powder Bed Fusion (LPBF), is essential to reveal the full potential of AM-processed metallic components. The application of powder blends represents a promising pathway for flexible adjustment of the chemistry of the raw material and thus, enables rapid alloy development for AM. This work demonstrates the possibility of precisely adjusting the C-content in Fe-Mn-C austenitic steel using blends of C and pre-alloyed X30Mn22 powders. Electron probe micro analysis (EPMA) and electron backscatter diffraction (EBSD) were used to investigate the elemental distribution, microstructure and the occurring deformation mechanisms of the as-built and deformed specimen. The results were correlated with the tensile properties. It was found that the applied approach enables reliable adjustment of the C-content and thus, of the microstructure and mechanical properties.